THE BLOOMING ICEHOUSE
1) Determine the distribution of Coscinodiscus excavatus from Site U1334
2) Document the maximum size of Coscinodiscus excavatus through quantitative morphometric analysis
3) Establish the timing and rapidity of size changes and relationship (if any) to environmental factors
Here we present quantitative abundance and morphometric analysis of 1200 specimens of Coscinodiscus excavatus from Site U1334. Samples were analysed at 1.5 metre intervals (90 kyr). Diatoms increase in size and abundance in the early Oligocene from 33.69 Ma. Specimens ranged in size from <120 microns to maximum sizes of 530 microns at 31.8 Ma. This was followed by a rapid decrease in size, with all specimens <150 microns from 31.10 Ma. Relative abundance data indicate a direct correlation between diatom abundance and maximum size. We use multispecies planktonic foraminiferal stable isotopes to reconstruct water column through this interval and explore the mechanism for the dramatic increase in diatom size in the earliest Oligocene.